Interleukin-6 produced by pancreatic carcinoma cells enhances humoral immune responses against tumor cells: a possible event in tumor regression.
Production of interleukin-6 (IL-6) by human pancreatic carcinoma cells inversely correlates with potentials for blood-borne metastasis to the liver in nude mice. IL-6 cDNA was transfected to PCI-43, one of our cultured pancreatic carcinoma cell lines that does not produce IL-6 and generates numerous metastases to the liver. An IL-6 high-producer clone (PCI-43h) generated few metastases; IL-6 production thus has a direct effect on metastasis, whereas other transfectants (PCI-43l and PCI-43n), which are IL-6 low-, and IL-6 non-producers, respectively, did generate metastases. Tumor-reactive IgG, which mediated antibody-dependent cellular cytotoxicity (ADCC) in vitro, was detected in sera from recipient nude mice inoculated with PCI-43h but not in sera from mice given PCI-43l, PCI-43n or parent PCI-43. Tumor-reactive IgM was detected in sera from all mice, irrespective of inoculated PCI-43 species, with a slight augmentation being noted in PCI-43h-inoculated nude mice. Severe combined immunodeficiency (SCID) beige mice were then used as recipients for PCI-43 species, and tumorigeneity was examined by s.c. inoculation of a suboptimal number of PCI-43 transfectants (1 x 10(6)/0.1 ml). Only PCI-43h formed palpable masses in SCID beige mice, whereas it first grew to be palpable but subsequently became not palpable in nude mice, thereby revealing a dual action of tumor-derived IL-6. Thus, tumor-derived IL-6 confers growth promotion in SCID beige mice, while the same cytokine exhibits anti-tumorigenic functions, presumably through humoral immune responses, in nude mice.
Saito
K
K
Department of Pathology, Hokkaido University School of Medicine, Sapporo, Japan.
Ishikura
H
H
Kishimoto
T
T
Kawarada
Y
Y
Yano
T
T
Takahashi
T
T
Kato
H
H
Yoshiki
T
T
D000818:Animals; D000912:Antibodies, Neoplasm / Q000096:biosynthesis*; D000920:Antibody-Dependent Cell Cytotoxicity; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D015850:Interleukin-6 / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016513:Mice, SCID; D010190:Pancreatic Neoplasms / Q000276:immunology*; D014407:Tumor Cells, Cultured
D000912:Antibodies, Neoplasm; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015850:Interleukin-6